Actinolite

Actinolite: mineral from the Amphibole group, chemically a silicate with the formula Ca2(Mg,Fe)5 [(OH,F) Si4O11]2. Ranges from transparent to translucent, with vitreous to silky luster. Crystallizes in the Monoclinic System and occurs in prismatic or acicular crystals, or in fibrous-radiating or elongated aggregates. Found in metamorphic rocks. Often mistaken for Asbestos.

(Photo: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0/Wikimedia Commons, License CC BY-SA 3.0)
(Photo: Didier Descouens/Wikimedia Commons, License CC BY-SA 4.0)

back to the gemological glossary